This study will examine laboratory and medical history data of participants who are already enrolled in the CARDIA study; there are no additional study visits specifically for this study. Toenail samples collected from participants during their Year 2 CARDIA study visit in the late 1980's will be examined to determine the presence of selenium, chromium, arsenic, and mercury. Participants' CARDIA study data will be reviewed and several CVD risk factors will be analyzed, including the thickness of heart arteries; calcium buildup within the arteries; inflammatory markers, such as high sensitivity C-reactive protein and interleukin 6; blood pressure levels; body weight; and levels of cholesterol, fat, and sugar.